JP2007329852A - Imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging apparatus hard to damage and capable of cost cutting, by simplifying the configuration of a half mirror with respect to the imaging apparatus, which can offer a through image while the half mirror is arranged inside the imaging light path. <P>SOLUTION: A half mirror 201 for reflecting object luminous flux to CCD 221 and leading transmission light to a ranging/photometry sensor 217 is fixed inside a mirror box, and a total reflection mirror 202, which can be moved at the rear face of the half mirror 201 and at a position evacuated from the optical path of lenses 101a, 101b, is provided. Upon display of a through image, the total reflection mirror 202 is located at the evacuated position, and during imaging, the total reflection mirror 202 is moved to the rear face of the half mirror 201 so that all of the objective luminous flux are led to the CCD 221. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a photographing apparatus having a through image display function, and more specifically, a so-called through image display function (also referred to as a live view display function or an electronic viewfinder function) for displaying an image acquired by an image sensor as a moving image on a display device. The present invention relates to a photographing apparatus.

In conventional photographing apparatuses such as digital cameras, the observation of subject images has been performed with an optical finder. Recently, however, the optical finder has been eliminated, and an imaging device provided for recording subject image data instead. Is also used for display. That is, there are an increasing number of images having a through image display function for displaying an image acquired by an image sensor on a display device such as a liquid crystal monitor for observing a subject image.

As a digital camera having such a through image display function, for example, Japanese Patent Application Laid-Open No. H10-228707 obtains a subject image to an imaging device by retracting a movable mirror from a photographing optical path and fully opening a focal plane shutter. An interchangeable lens camera that continuously displays a subject image on a liquid crystal monitor is disclosed. However, in Patent Document 1, a TTL (Trough The Lens) phase difference AF (Auto Focus) generally adopted in a conventional camera is used in order to retract the movable mirror out of the photographing optical path during live view display. There is a problem that can not be done.
JP 2002-369042 A

Therefore, Patent Document 2 proposes a digital camera in which a movable mirror is configured by a half mirror, and a subject light beam that has passed through a photographing optical system is guided to both an image sensor and a phase difference AF sensor. According to this configuration, phase difference AF is also possible while displaying a through image, and the above-described problem can be solved.
Japanese Patent Laid-Open No. 2002-6208

However, when a configuration in which a half mirror is arranged in a photographing optical path as in Patent Document 2 is applied to a digital camera, the following problem may occur. In other words, since the incident angle of the principal ray that passes through the half mirror varies depending on the position of the half mirror, the optical path length changes depending on the image height, so that a difference occurs in the aberration of each image height. For this reason, for example, even if the change in the optical path length at the center of the screen is corrected, the optical path length at each image height is not uniform, so that the uniformity of the image quality of the subject image is impaired. In order to reduce this change in aberration, the half mirror should be made as thin as possible. On the other hand, in order to increase the amount of subject light and to obtain an image free of aberrations during shooting, the half mirror must be retracted from the shooting optical path. Is required. In order to eliminate the influence of aberration, it is necessary to make the half mirror thin, but the strength is also necessary, and it is difficult to satisfy conflicting elements at the same time, resulting in an increase in cost. There is also a problem that it is easily damaged because it is thinned.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a photographing apparatus that can simplify the configuration of the half mirror, reduce the cost, and is not easily damaged.

In order to achieve the above object, a photographing apparatus according to a first aspect of the invention receives a subject mirror reflected by a half mirror that reflects a part of a subject light beam incident through a photographing lens and a subject light beam reflected by the half mirror. In response to a release operation, an image capturing unit that outputs an image signal, a still image recording unit that records a subject image signal output from the image capturing unit as a still image, and an operation start of the still image recording unit, A movable reflecting mirror is provided that guides the light beam that has been moved from the retracted position to the back surface of the half mirror and transmitted through the half mirror to the imaging means.

When the movable reflecting mirror is in the retracted position in the first invention, the imaging apparatus according to the second invention repeatedly images the subject light beam reflected by the half mirror by the imaging means, A through image display operation is performed based on the output.
According to a third aspect of the present invention, there is provided a photographing apparatus according to the first aspect, further comprising distance measuring means for detecting a focus state of the photographing lens by a light beam transmitted through the half mirror.
Further, according to a fourth aspect of the present invention, in the third aspect, the movable reflecting mirror is retracted after the still image recording operation is completed.
Furthermore, a photographing apparatus according to a fifth aspect of the present invention includes the photometric means for measuring subject luminance by the light beam transmitted through the half mirror in the first aspect.
Further, in the photographing apparatus according to a sixth aspect of the present invention, in the first aspect, the half mirror is fixed in a mirror box.

In order to achieve the above object, a photographing apparatus according to a seventh aspect of the present invention includes a half mirror fixed in a mirror box that reflects part of a subject light beam incident through a photographing lens and transmits the remaining part, and the half mirror. And a total reflection mirror that can be moved to a retracted position that does not block the subject light flux.

According to an eighth aspect of the present invention, in the seventh aspect, the total reflection mirror is in a normal retreat position.
An imaging device according to a ninth invention is the imaging device according to the seventh invention, comprising: an imaging element provided on the reflected optical path of the half mirror; and a distance measuring sensor provided on the transmitted optical path of the half mirror. It has.
Further, in the photographing apparatus according to a tenth aspect, in the seventh aspect, the total reflection mirror moves to the back position at the time of photographing and moves to the retracted position at the end of photographing.

According to the present invention, as the operation of the still image recording unit is started, the movable reflecting mirror that moves from the retracted position to the back position of the half mirror and transmits the light beam transmitted through the half mirror to the imaging unit is provided. It is possible to provide a photographing apparatus that can simplify the configuration of the half mirror, reduce the cost, and hardly break.

Hereinafter, a preferred embodiment using a digital camera to which the present invention is applied will be described with reference to the drawings. FIG. 1 is an external perspective view of a digital camera according to an embodiment of the present invention as viewed from the back. This camera is composed of a camera body 20 and a lens barrel 10 as an interchangeable lens. The lens barrel 10 is detachable from a mount opening (not shown) on the front surface of the camera body 20. The subject luminous flux from the photographing lens including the lenses 101a, 101b, etc. (see FIG. 2) in the lens barrel 10 is guided into the camera body 20 through the mount opening. In the present embodiment, the lens barrel 10 and the camera body 20 are configured separately and are electrically connected via a communication contact 300 (see FIG. 2). Also, the attachment / detachment state can be detected by an attachment / detachment detection switch 259 (see FIG. 2) provided in the camera body 20.

On the upper surface of the camera body 20, a release button 21, a mode dial 22, a power switch lever 23, a control dial 24, and the like are arranged. The release button 21 has a first release switch that is turned on when the photographer is half-pressed and a second release switch that is turned on when the photographer is fully pressed. When the first release switch (hereinafter referred to as 1R) is turned on, the camera performs photographing preparation operations such as focus detection, focusing of the photographing lens, and photometry of the subject brightness, and the second release switch (hereinafter referred to as 2R). When it is turned on, a photographing operation for capturing image data of a subject image is executed based on the output of a CCD (Charge Coupled Devices) 221 (see FIG. 2) as an image sensor.

The mode dial 22 is an operation member that is configured to be rotatable. By matching a picture display or symbol representing a shooting mode provided on the mode dial 22 with an index, a full-auto shooting mode (AUTO) or a program shooting mode is set. (P), aperture priority shooting mode (A), shutter speed priority shooting mode (S), manual shooting mode (M), portrait shooting mode, landscape shooting mode, macro shooting mode, sports shooting mode, night scene shooting mode, etc. Each shooting mode can be selected. The power switch lever 23 is an operation member for turning on / off the power supply of the digital camera, and is configured to be rotatable at two positions, on / off. The control dial 24 is an operation member configured to be rotatable, and a desired set value, mode, or the like can be selected by rotating the control dial 24 on an information display screen or the like.

On the back of the camera body 20, a rear liquid crystal monitor 26, a playback button 27, a menu button 28, a cross button 30, an OK button 31, and a viewfinder eyepiece 33 are arranged. The rear liquid crystal monitor 26 is a display device for displaying a subject image as a through image for observation, reproducing and displaying a photographed subject image, and displaying camera information and menus. Any liquid crystal display can be used as long as it can perform these displays. Note that the camera body 20 may be configured to freely change the angle. The viewfinder eyepiece 33 is an eyepiece window for observing a subject image, and an in-finder liquid crystal monitor 29 described later is disposed therein, and the subject image can be observed through the finder eyepiece 33. Yes. The playback button 27 is an operation button for instructing to display a subject image recorded after shooting on the rear liquid crystal monitor 26. In accordance with the operation of the playback button 27, the image data of the subject stored in the later-described SDRAM 238 or the recording medium 245 in the compression mode such as JPEG is expanded and then displayed on the rear liquid crystal monitor 26.

The cross button 30 is an operation member for instructing the movement of the cursor in the two-dimensional direction of the X direction and the Y direction on the rear liquid crystal monitor 26, and for displaying the subject image recorded on the recording medium 245. Also used to select playback images. In addition to providing four buttons for up, down, left, and right, it is also possible to replace with a switch that can be operated in a two-dimensional direction, such as a switch that can detect the operation direction in two dimensions, such as a touch switch. is there. The OK button 31 is an operation member for confirming various items selected by the cross button 30, the control dial 24, or the like. The menu button 28 is a button for switching to a menu mode for setting various modes of the digital camera. When the menu mode is selected by operating the menu button 28, a menu screen is displayed on the rear liquid crystal monitor 26. . The menu screen has a plurality of hierarchical structures. Various items are selected with the cross-shaped button 30, and selection is determined by operating the OK button 31.

The release button 21, the power switch lever 23, the playback button 27, the menu button 28, the cross button 30, and the OK button 31 are all linked to the on / off switch. Signals generated in response to the operation of the operation buttons linked to these on / off switches and the operation members such as the mode dial 22 and the control dial 24 are detected by the switch in an ASIC (Application Specific Integrated Circuit) 262. It is transmitted to the circuit 253 (see FIG. 2).

Next, referring to FIG. 2, an overall configuration mainly including an electric system of the digital camera will be described.
Inside the lens barrel 10, there are disposed lenses 101a and 101b for focus adjustment and focal length adjustment, and a diaphragm 103 for adjusting the aperture. The lens 101 a and the lens 101 b are driven by an optical system driving mechanism 107, and the diaphragm 103 is connected to be driven by a diaphragm driving mechanism 109. The optical system driving mechanism 107 and the aperture driving mechanism 109 are each connected to a lens CPU 111, and the lens CPU 111 is connected to the camera body 20 via a communication contact 300. The lens CPU 111 controls the lens barrel 10 and controls the optical system driving mechanism 107 to perform focusing and zoom driving, and also controls the aperture driving mechanism 109 to control the aperture value.

In the mirror box in the camera body 20, a half mirror 201 having a characteristic of transmitting a part of the light flux that has passed through the lenses 101a and 101b and reflecting the rest is disposed. The half mirror 201 is fixed in the mirror box with an inclination of 45 degrees with respect to the optical paths of the lenses 101a and 101b. A movable reflection mirror 202 is provided that can be rotated between a back surface position along the back surface of the half mirror 201 (on the side opposite to the lenses 101a and 101b) and a retreat position of the bottom in the mirror box. The movable reflecting mirror 202 is driven by a mirror driving mechanism 215 and can be rotated about an axis in a direction perpendicular to the paper surface about a rotation axis 202a. When the movable reflecting mirror 202 is retracted to the bottom of the mirror box, a part (for example, 30%) of the subject light flux is transmitted and guided to the distance measuring / photometric sensor 217 disposed in the transmitted light path. The remainder (70%) of the subject luminous flux is reflected by the half mirror 201 and guided in the direction of the CCD 221. When the movable reflecting mirror 202 is in a position in close contact with the back surface of the half mirror 201, the entire subject light beam is reflected and guided to the CCD 221. The structures of the half mirror 201 and the movable reflection mirror 202 will be described later with reference to FIG. In the present embodiment, the center of rotation of the movable reflecting mirror 202 is the lower side in the mirror box. However, the center of rotation is not limited to this, and may be the upper side. Of course, the center of rotation may be used. In the present embodiment, the reflectance and transmittance of the half mirror are 70% and 30%, respectively, but are not limited to this ratio and can be changed as appropriate.

A distance measuring / photometric sensor 217 is arranged at the back of the mirror box in the camera body 20 and at a position where the transmitted light of the half mirror 201 is guided. The distance measuring / photometric sensor 217 includes a distance measuring sensor and a photometric sensor. The photometric sensor includes a multi-division photometric element that divides a subject image and performs photometry. The distance measuring sensor is a sensor for measuring a distance by the TTL phase difference method. The output of the distance measurement / photometry sensor 217 is sent to the distance measurement / photometry processing circuit 219. The distance measurement / photometry processing circuit 219 outputs an evaluation photometric value based on the output of the photometry sensor, and measures the focus shift amount of the subject image formed by the lenses 101 and 101b based on the output of the distance measurement sensor. To do. Note that the distance measuring sensor and the photometric sensor may be configured separately or integrally.

A focal plane type shutter 203 for controlling exposure time and shielding the CCD 221 is disposed above the half mirror 201 and on the optical path of light reflected by the half mirror 201. The shutter 203 is a shutter drive mechanism. Drive control is performed by 213.

An infrared cut filter 209 for cutting infrared light components from the subject light beam is disposed behind the shutter 203, and an optical low-pass filter 210 for removing high frequency components from the subject light beam is disposed behind the shutter 203. ing. A CCD 221 serving as an image sensor is disposed behind the optical low-pass filter 210, and subjects images formed by the lenses 101a and 101b are photoelectrically converted into electric signals. The dustproof filter 205, the infrared cut filter 209, the optical low-pass filter 210, and the CCD 221 are integrally stored in a sealed package (not shown) so that dust does not enter the package. In the present embodiment, a CCD is used as an image sensor. However, the present invention is not limited to this, and a CMOS (Complementary Metal Oxide) is used.
Needless to say, a two-dimensional imaging device such as Semiconductor) can be used.

The CCD 221 is connected to the image sensor driving circuit 223 and is driven and controlled by a control signal from the input / output circuit 239. A photoelectric analog signal output from the CCD 221 is amplified and analog-digital converted (AD converted) by the image sensor driving circuit 223. The image sensor driving circuit 223 is connected to an image processing circuit 227, and the image processing circuit 227 performs digital amplification (digital gain adjustment processing) of digital image data, color correction, gamma (γ) correction, contrast correction, monochrome / color mode. Various image processing such as processing and through image processing are performed. The image processing circuit 227 is connected to the data bus 261. In addition to the image processing circuit 227, the data bus 261 includes a sequence controller (hereinafter referred to as "body CPU") 229, a compression / decompression circuit 231, a video signal output circuit 233, an SDRAM control circuit 237, and an input / output circuit 239. A communication circuit 241, a recording medium control circuit 243, a flash memory control circuit 247, and a switch detection circuit 253 are connected.

The body CPU 229 connected to the data bus 261 controls the operation of this digital camera. A compression / decompression circuit 231 connected to the data bus 261 is a circuit for compressing image data stored in the SDRAM 238 by JPEG or TIFF. Note that image compression is not limited to JPEG or TIFF, and other compression methods can be applied. The video signal output circuit 233 connected to the data bus 261 is connected to the rear liquid crystal monitor 26 and the finder liquid crystal monitor 29 (abbreviated as “F liquid crystal monitor” in the figure) via the liquid crystal monitor drive circuit 235. The video signal output circuit 233 is a circuit for converting the image data stored in the SDRAM 238 or the recording medium 245 into a video signal for display on the rear liquid crystal monitor 26 and / or the in-viewfinder liquid crystal monitor 29. The rear liquid crystal monitor 26 is disposed on the rear surface of the camera body 20. However, the rear liquid crystal monitor 26 is not limited to the rear surface and may be other display devices as long as the photographer can observe. The in-viewfinder liquid crystal monitor 29 is disposed at a position where it can be observed by the photographer through the viewfinder eyepiece 33, and like the rear liquid crystal monitor 26, other liquid crystal display devices may be used. Note that only the rear liquid crystal monitor 26 may be used for observation of the subject image, and the finder eyepiece 33 and the finder liquid crystal monitor 29 may be omitted.

The SDRAM 238 is connected to the data bus 261 via the SDRAM control circuit 237, and the SDRAM 238 temporarily stores the image data processed by the image processing circuit 227 or the image data compressed by the compression / expansion circuit 231. This is a buffer memory. The input / output circuit 239 connected to the shutter drive mechanism 213, the movable mirror drive mechanism 215, and the distance measurement / photometry processing circuit 219 controls data input / output with each circuit such as the body CPU 229 via the data bus 261. . The communication circuit 241 connected to the lens CPU 111 via the communication contact 300 is connected to the data bus 261, and exchanges data with the body CPU 229 and the like and communicates control commands.

A recording medium control circuit 243 connected to the data bus 261 is connected to the recording medium 245 and controls recording of image data and the like on the recording medium 245. The recording medium 245 can be loaded with any rewritable recording medium such as an xD picture card (registered trademark), a compact flash (registered trademark), an SD memory card (registered trademark), or a memory stick (registered trademark). And is detachable from the camera body 20. In addition, a hard disk unit such as a microdrive (registered trademark) or a wireless communication unit may be connectable.

A flash memory control circuit 247 connected to the data bus 261 is connected to a flash memory 249. The flash memory 249 stores a program for controlling the flow of the camera. The digital camera is controlled according to the program stored in the flash memory 249. Note that the flash memory 249 is an electrically rewritable nonvolatile memory.

A power switch 257 that is turned on / off in conjunction with a power switch lever 23 for controlling the power supply of the camera body 20 and the lens barrel 10, and a switch that detects the first stroke and the second stroke of the shutter release button 21. A switch linked to the playback button 27 for instructing the playback mode, a switch linked to the cross button 30 for instructing the movement of the cursor on the screen of the rear liquid crystal monitor 26, and a switch linked to the mode dial 22 for instructing the shooting mode. In addition, various switches 255 such as an OK switch linked to an OK button 31 for determining each mode and the like, and the attachment / detachment detection switch 259 are connected to the data bus 261 via the switch detection circuit 253.

Next, the drive means and retracting means of the movable reflecting mirror 202 will be described with reference to FIG. The half mirror 201 that transmits a part of the subject luminous flux and reflects a part thereof is fixed and held by a fixed frame (not shown) and forms an angle of 45 degrees with respect to the optical paths of the lenses 101a and 101b. The mirror frame that holds the movable reflecting mirror 202 is rotatable about a rotation shaft 202a, and a drive pin 202b is fixed on the side surface of the mirror frame. A drive lever 401 having a U-shaped portion that engages with the drive pin 202b has a rotating shaft 401a supported on the camera body 20.

At normal times, the drive lever 401 is urged by a spring (not shown) so that the movable reflecting mirror 202 is at the position shown in FIG. 3A where it is retracted from the optical path of the lenses 101a and 101b. When the other end of the drive lever 401 is driven in the direction of arrow A by a drive mechanism (not shown), the movable reflecting mirror 202 is counterclockwise against the urging force of the spring as shown in FIG. It rotates and becomes a position along the back surface of the half mirror 201. When the drive lever 401 is rotated clockwise in this state, the movable reflecting mirror 201 returns to the retracted position in FIG. The drive lever 401 may be driven by a motor, an electromagnet, or the like.

Next, the operation of the digital camera in one embodiment of the present invention will be described using the flowcharts shown in FIGS. When the power-on reset flow shown in FIG. 4 is entered, it is determined whether the power switch 257 of the camera body 20 is turned on (S1). As a result of the determination, if the power switch 257 is off, the process proceeds to step S5 to enter a sleep state that is a state of low power consumption. In this sleep state, interrupt processing is performed only when the power switch 257 is turned on, and processing for turning on the power switch is performed in step S9 and subsequent steps. Until the power switch is turned on, operations other than power switch interrupt processing are stopped to prevent the power battery from being consumed.

In step S1, when the power switch 257 is on, the process proceeds to step S3, and it is determined whether the attach / detach switch 259 is off. As described above, the attachment / detachment detection switch 259 is a switch that is turned off when the lens barrel 10 is removed from the camera body 20. If it is off, that is, if the lens barrel 10 is detached, the process proceeds to step S51 described later. This is because when the power switch lever 23 of the camera body 20 is operated and the power is turned on while the lens barrel 10 is detached, the same processing as when the lens is detached is performed. If it is determined in step S3 that the detachable switch 259 is on, the process proceeds to step S9 and subsequent steps, and processing for turning on the power switch is performed.

First, in step S9, the shutter 203 is opened by the shutter drive circuit 213 (S9). Since the half mirror 201 is fixed in the mirror box, the subject luminous flux that has passed through the lenses 101 a and 101 b is reflected by the half mirror 201 toward the CCD 221. When the shutter 203 is opened in this state, the subject light beam reflected by the half mirror 201 is not blocked by the shutter 203, so that a subject image is formed on the CCD 221. Subsequently, an instruction is given to start the live view display for displaying the subject image as a moving image on the rear liquid crystal monitor 26 using the image data captured by the CCD 221 (S11). The through image display operation is controlled by the image processing circuit 227 in response to the start instruction.

Next, if there is information such as the shooting mode set by the mode dial 22 or the like, ISO sensitivity, manually set shutter speed or aperture value, those shooting conditions are read (S13). Then, the subject brightness is measured by the distance measuring / photometric sensor 217, the exposure amount is calculated, and exposure control values such as a shutter speed and an aperture value are calculated according to the shooting mode and shooting conditions using the exposure amount (S15). . Further, through image display setting is performed using a photometric value, an exposure amount, and the like (S17). In this step, in order to set the electronic shutter speed and sensitivity conditions for driving the CCD 221, using the photometry / exposure calculation result obtained in step S15 or the previous display image, the rear liquid crystal monitor 26 and / or Alternatively, calculation and setting for displaying an image of appropriate brightness (brightness) on the liquid crystal 29 in the finder is performed.

Next, it progresses to step S19 and it is determined whether it is a reproduction | regeneration mode. This playback mode is a mode in which when the playback button 27 is operated, still image data recorded on the recording medium 245 is read and displayed on the rear liquid crystal monitor 26 and / or the finder liquid crystal 29. If the reproduction mode is set as a result of the determination, the process proceeds to step S31 to instruct the image processing circuit 227 to stop the through image display. Thereafter, after closing the shutter 203 (S33), the still image data recorded on the recording medium 245 is read out, the image data is expanded by the compression / expansion circuit 231, and the video signal output circuit 233 and the liquid crystal monitor are read out. The still image is reproduced and displayed on the rear liquid crystal monitor 26 and / or the finder liquid crystal 29 via the drive circuit 235 (S35). If another manual operation such as half-pressing of the release button 21 is performed during the reproduction operation, the reproduction operation is terminated and the process returns to step S9 to repeat the above-described operation.

Returning to step S19, if the playback mode has not been set, the process proceeds to step S21 to determine whether the menu mode has been set. This determines whether the menu button 28 is operated and the menu mode is set. As a result of the determination, if the menu mode is set, a through image stop instruction is output (S37) and a close command is output to the shutter 203 (S39), as in the case where the playback mode is set. Thereafter, a menu setting operation is performed (S41). Various setting operations such as white balance, ISO sensitivity setting, and drive mode setting can be performed by the menu setting operation. When the menu setting operation is completed, the process returns to step S9, and the above operation is repeated.

Returning to step S21, if the result of determination is that the menu mode has not been set, processing proceeds to step S23, where it is determined whether the release button 21 has been pressed halfway, that is, whether the 1R switch is on. If the result of determination is that 1R is on, processing advances to step S43, and a shooting operation subroutine for shooting preparation and shooting is executed. Details of this subroutine will be described later with reference to FIG. When the photographing operation subroutine ends, the process returns to step S9 to repeat the above steps.

Returning to step S23, if the result of determination is that the 1R switch is off, processing proceeds to step S25, where it is determined whether the attachment / detachment detection switch 259 is off, as in step S3. When the lens barrel 10 is detached, a through image stop instruction is output (S45) and the shutter 203 is closed (S47), as in steps S31 and S33 in the reproduction mode.

When the closing operation of the shutter 203 is completed, or when it is determined in step S3 that the attachment / detachment detection switch 259 is off (that is, when the lens barrel 10 is detached), the process proceeds to step S51, and attachment / detachment detection is performed. It is determined whether the switch 259 is on. In step S25, after detecting that the lens barrel 10 is detached, it is determined whether or not the lens barrel 10 is attached again. As a result of the determination, if it is mounted, the process returns to step S9 and the above steps are repeated.

Returning to step S51, if the attachment / detachment detection switch 259 is off, the process proceeds to step S53 to determine whether the power switch 257 is on. When the lens barrel 10 is detached and the power switch 257 is on, the mount opening remains open even when various operation buttons are operated. Therefore, from the viewpoint of preventing malfunction, the camera operation should not be performed. Yes. For this reason, the lens barrel 10 is attached in step S51 and the standby state in which the determination of the operation state of the power switch lever 23 is repeated in step S53. If it is determined in step S53 that the power switch 257 is off, the process returns to step S5 and enters a sleep state. In step S51, when it is detected that the lens barrel 10 remains detached, the determination in step S53 may be omitted, and the process may proceed to step S5 to enter the sleep state, or the process may proceed to step S9. Modifications such as performing an operation based on an operation by the operation button are possible.

Returning to step S25, if the result of determination is that the attachment / detachment detection switch 259 is on, that is, if the lens barrel 10 is attached to the camera body, the routine proceeds to step S27, where it is determined whether or not the power switch 257 is on. If the result of determination is that it is on, processing returns to step S13 and the above steps are repeated. In step S11, after the live view display is started, the subject light flux that has passed through the half mirror 201 is not blocked by the shutter 203 unless various operation buttons and the like are operated in step S19 and subsequent steps, so that the subject image is displayed on the CCD 221. The image data formed and imaged by the CCD 221 is displayed as a moving image on the rear liquid crystal monitor 26 and / or the finder liquid crystal 29 as a moving image. If it is determined in step S27 that the power switch 257 is off, as in steps S31 and S33, the image processing circuit 227 is instructed to stop displaying the through image (S28), and the shutter 203 is closed. (S29). Thereafter, the process returns to step S5 to enter the sleep state.

As described above, in the present embodiment, in the digital camera capable of displaying a through image, the half mirror 201 is fixed in the photographing optical path, and a part of the subject luminous flux is guided to the distance measuring / photometric sensor 217. It is convenient to display a live view immediately after power-on and to perform photometry and distance measurement.

Next, the shooting operation subroutine of step S43 will be described with reference to FIG. As described above, this subroutine is executed when the release button 21 is half-pressed. First, distance measurement and automatic focus adjustment are performed (S71). The half mirror 201 is fixed in the mirror box, and a part of the subject luminous flux is transmitted through the half mirror 201 and guided to the distance measuring / photometric sensor 217. 219, the body CPU 229, and the like detect the focal shift amount of the lenses 101a and 101b by the TTL phase difference method, and the lens is moved to the focus position by the optical system driving mechanism 107 via the lens CPU 111 based on the detected focal shift amount. 101a and 101b are driven.

Next, photometry / exposure amount calculation is performed (S73). Also in this case, the subject luminous flux transmitted through the half mirror 201 is received by the distance measuring / photometric sensor 217 and processed by the distance measuring / photometric processing circuit 219 to detect the subject luminance BV. The body CPU 229 obtains the exposure amount EV using the subject luminance BV, and further obtains the exposure conditions such as the shutter speed and the aperture according to the photographing mode.

Next, it is determined whether or not the release button 21 is fully pressed, that is, whether or not 2R is on (S75). If the result of determination is that it is off, processing advances to step S77 to determine whether 1R is on. If the release button 21 is half-pressed to jump to this shooting operation subroutine and the release button 21 remains half-pressed, a standby state is made in which the determination is repeated in steps S75 and S77. When the hand is released from the release button 21 and 1R is turned off, the process returns to the power-on reset step S9.

Returning to step S75, if the result of determination is that the 2R switch is on, that is, if the release button 21 is fully pressed, the operation moves to an imaging operation for acquiring a still image. First, in step S79, a through image stop instruction is output to the image processing circuit 227. When acquiring a still image, the subject image incident on the CCD 221 is disturbed by the movement of the half mirror 201 to the retracted position, the opening / closing operation of the shutter 203, and the like, and the through liquid crystal monitor 26 and / or the liquid crystal 29 in the finder is through. This is to prevent the image from becoming unsightly. Then, the advance operation of the movable reflecting mirror 202 is performed (S81). This is accomplished by rotating the drive lever 401 in the A direction (counterclockwise) by a drive mechanism (not shown) and moving it from the state shown in FIG. 3A to the position shown in FIG. As a result, all of the subject luminous flux that has passed through the lenses 101 a and 101 b is reflected by the half mirror 201 and the movable reflecting mirror 202 and guided toward the CCD 221.

Subsequently, the aperture driving mechanism 109 performs the aperture operation of the aperture 103 to the set aperture value or the aperture value calculated in S73 through the lens CPU 111. When the narrowing-down operation is completed, an exposure operation by the CCD 221 is then performed (S85). That is, since the movable reflecting mirror 202 has moved from the retracted position to the advanced position, all of the subject luminous flux that has passed through the lenses 101a and 101b is guided onto the light receiving surface of the CCD 221 to form a subject image. . In this state, the reset of the electronic shutter of the CCD 221 is released, and charge accumulation of the photoelectric conversion current of the subject image is started. When the exposure time set in advance or set in step S73 has elapsed, the electronic shutter of the CCD 221 stops the charge accumulation of the photoelectric conversion signal. In the exposure operation in step S85, the exposure time is controlled by the electronic shutter of the CCD 221. However, the present invention is not limited to this, and the exposure time can also be controlled by the shutter 203. In this case, it is necessary to once move the front and rear curtains of the shutter 203 to the initial positions before the start of the exposure operation.

Subsequently, the shutter 203 is closed (S87), and an instruction to open the aperture 103 is output to the lens CPU 111 (S89). Further, the image signal stored in the CCD 221 is read (S91), and image processing is performed by the image processing circuit 227 or the like (S93). After processing such as signal compression in the compression / decompression circuit 231, image data is recorded on the recording medium 245 (S95). When the recording of the image data is finished, it is determined in step S97 whether the 1R switch is on, that is, whether the release button 21 is half pressed. When the 1R switch is turned off, the process proceeds to step S99, and the movable reflecting mirror 202 is returned to the retracted position. This is done by rotating the drive lever 401 clockwise to return from the state of FIG. 3 (B) to the state of FIG. 3 (A). When the return operation is completed, the routine returns to the power-on reset routine.

In the present embodiment, the half mirror 201 is provided in the mirror box, and the subject light flux is divided and guided to the distance measuring sensor and the CCD 221 which is the imaging element in the normal state. It can be carried out. Therefore, when the release button 21 is pressed halfway during live view display and 1R is turned on, photometry and distance measurement can be performed immediately in parallel with live view display. In addition, since the half mirror 201 is fixed, the thickness thereof can be reduced. Therefore, the change in the amount of aberration based on the difference in the optical path length in the half mirror can be minimized.

In addition, during the imaging operation for acquiring a still image, the movable reflection mirror 202 that is a total reflection mirror is rotated on the back surface of the half mirror 201. For this reason, the subject luminous flux that passes through the half mirror 201 is also reflected by the movable reflecting mirror 202 and guided to the CCD 221, so that the subject light quantity can be increased from the through image display when acquiring a still image, and shooting at a high shutter speed is possible. It becomes possible.

Further, when the imaging operation is completed, since the total reflection mirror 202 is returned in step S99, when the release button 21 is half-pressed again after shooting, photometry and distance measurement are immediately performed in parallel with the live view display. It can be carried out.

In the present embodiment, the camera ranging operation is started by pressing the release button 21 halfway. As a modified example, when the continuous ranging mode is selected, steps S71 and S73 may be repeated at predetermined time intervals. In this case, continuous distance measurement may be performed only while the release button 21 is half-pressed.

In the present embodiment, the present invention is applied to a general digital camera. However, the present invention is not limited to this, and may be a photographing device in various devices such as a portable device, and is equipped with a bellows, an extension tube, or the like. Of course, the present invention can also be applied to a dedicated camera attached to various devices such as a microscope and binoculars.

It is the external appearance perspective view which looked at the digital camera in one Embodiment of this invention from the back surface. It is a block diagram which shows the whole structure of the electric system of the digital camera in one Embodiment to which this invention is applied. It is a perspective view which shows the components structure of the half mirror and the total reflection mirror in one Embodiment of this invention. It is a flowchart which shows the operation | movement of the power-on reset in one Embodiment of this invention. 6 is a flowchart of a shooting operation according to an embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Lens barrel 20 Camera main body 21 Release button 23 Power switch lever 26 Back surface liquid crystal monitor 29 In-finder liquid crystal monitor 33 Viewfinder eyepiece 101a, 101b Lens 103 Diaphragm 111 Lens CPU
201 Half mirror 202 Total reflection mirror 202a Rotating shaft 202b Drive pin 203 Shutter 209 Infrared cut filter 210 Optical low-pass filter 215 Movable mirror drive mechanism 217 Distance / photometry sensor 219 Distance / photometry processing circuit 221 CCD
227 Image processing circuit 229 Body CPU
253 Switch detection circuit 255 Various switches 257 Power switch 259 Detachment detection switch 261 Data bus 401 Drive lever 401a Rotating shaft

Claims (10)

A half mirror that reflects a portion of the subject luminous flux incident through the taking lens;
Imaging means for receiving a subject luminous flux reflected by the half mirror and outputting a subject image signal;
A still image recording means for recording a subject image signal output from the imaging means as a still image in response to a release operation;
In response to the start of the operation of the still image recording means, a total reflection mirror that moves from the retracted position to the back position of the half mirror and transmits the light beam that has passed through the half mirror to the imaging means,
An imaging apparatus comprising:   The object light beam reflected by the half mirror is repeatedly imaged by the imaging means when the total reflection mirror is in the retracted position, and a through image display operation is performed based on the output. The imaging apparatus according to 1.   2. The photographing apparatus according to claim 1, further comprising a distance measuring unit that detects a focus state of the photographing lens by a light beam transmitted through the half mirror.   The photographing apparatus according to claim 1, wherein the total reflection mirror is retracted after the still image recording operation is finished.   2. The photographing apparatus according to claim 1, further comprising photometric means for measuring subject brightness with a light beam transmitted through the half mirror.   The photographing apparatus according to claim 1, wherein the half mirror is fixed in a mirror box. A half mirror fixed in a mirror box that reflects part of the subject luminous flux incident through the taking lens and transmits the rest;
A total reflection mirror movable to the back position of the half mirror and a retracted position that does not block the subject luminous flux;
An imaging apparatus comprising:   The photographing apparatus according to claim 7, wherein the total reflection mirror is in a normal retreat position.   The imaging apparatus according to claim 7, further comprising: an image sensor provided on a reflection optical path of the half mirror; and a distance measuring sensor provided on a transmission optical path of the half mirror.   8. The photographing apparatus according to claim 7, wherein the total reflection mirror moves to the back position at the time of photographing and moves to the retracted position at the end of photographing.